As the world's supply of crude oil dwindles, processes such as Fisher-Tropsch synthesis and coal-to-Liquid (CTL) may become more economically viable, and increased usage of these technologies has been proposed. Both Fisher-Tropsch and coal-to-liquid processes generate substantial amounts of light condensate streams rich in olefins. As the demand for jet fuel and diesel fuel increases, there is more interest in converting the light condensate streams into distillate range products, particularly for jet fuel, diesel fuel, and lube base stock. However, conventional processes offer only limited options for upgrading the condensate into distillate or lube base stock range products.
In general, oligomerization reactions have been applied widely in the chemical and petroleum industries, including olefin oligomerization for the conversion of olefins to heavier products. With respect to applications for upgrading condensate, zeolite based catalysts have failed to achieve high conversion of olefins. In addition, zeolite based catalysts do not provide high levels of selectivity towards distillate range material, having a tendency to make lighter (less valuable) products. Furthermore, zeolite based catalysts for olefin conversions are prone to fairly rapid deactivation, while an alternative H3PO4 based oligomerization process tends to provide low quality products.
It can be seen that there is a need for improved processes for condensate upgrading that provide higher rates of olefin conversion into distillate, improved selectivity, and steady state catalytic activity for extended periods.